Means for cooling lubricating oil in submerged motors



June 12, 1951 MQEHRL HAL 2,556,435

MEANS FOR COOLING LUBRICATING OIL IN SUBMERGED MOTORS Filed April 27,1950 2 Sheets-Sheet 1 SUCTION NOZZLE 12% Z. 1 J //vm=ro e/5 tam 5r .e'.hoe/m4 65442158 8 P0 TER JR}.

June 12, 1951 K. E. MOEi-IRL ETAL 2,556,435

MEANS FOR COOLING LUBRICATING OIL IN SUBMERGED MOTORS Filed April 27,1950 2 Sheets-Sheet 2 m rwrwP twwera 5, 8A1 61/44465 6. 752 J2 PatentedJune l2, 1951 MEANS FOR COOLIN G LUBRICATING OIL IN SUBMERGED MOTORSKenneth E. Moehrl and Charles B. Porter, Jr., Memphis, Tenn., assignorsto Layne & Bowler, Incorporated, Memphis, Tenn., a corporation ofDelaware Application April 27, 1950, Serial No. 158,394

10 Claims.

This invention relates to means for cooling the lubricating oil usedwith submerged electric motors such as drive the centrifugal pumpslargely used in deep well pumping.

In this type of pumping the motor is enclosed in a casing as nearlyhermetically sealed as possible against inflow of water, and the casingaround the motor is substantially filled with lubrieating oil, and isdisposed below the pump with the motor shaft extending through astufiing box or seal for connection to the pump, or if not so filled,every endeavor is used to divert the oil used in lubrication to themotor bearings, and away from the rotor and stator coils and away fromthe gap therebetween. The oil within the casing is often stagnant andbecomes overheated, and even if circulated, provision is not made forcooling the oil and little or no provision is made for using the oil tocool the rotor and stator coils.

The objects of the present invention are to provide in an enclosedsubmergible motor, a motor casing substantially filled with lubricatingoil, and to provide:

Means for circulating the oil within the motor casing;

Means for circulating the oil in the motor casing through the gapbetween the rotor and stator coils of the motor;

Means for withdrawing the oil from a sump below the motor and throughthe gap between the coils and for returning the oil to the sump;

Means for circulating the oil within the motor casing and cooling theoil; and

Means for circulating the oil within the motor casing, and from a sumpbelow the coils, through the gap between the motor coils, cooling theoil and returning the oil to the sump by-passing the gap.

The means by which the foregoing and other objects of the invention areaccomplished and the manner of their accomplishment will readily beunderstood from the following specification upon reference to theaccompanying drawings, in which:

Fig. 1 is a sectional elevational view of an electric motor inaccordance with our invention showing means for effecting oilcirculation and cooling.

Fig. 2 is an elevational view on a smaller scale showing the motorcasing and its relation to a tandem type deep well pump.

Fig. 3 is a sectional elevational view of a motor similar to that shownin Fig. 1 with a modified means for effecting the cooling of the oil;and

Fig. 4 is a sectional elevational view of a stuffing box and seal forthe motor, showing the oil passage returning from the cooling meanspassing through the seal.

Fig. 5 is a sectional plan view taken as on the line VV of Fig. 3.

Referring now to the drawings in which the various parts are indicatedby numerals: I2 are pump bowls connected in tandem, to form a multistagewater pump used in deep well pumping. The bowls enclose pump impellers(not shown) which are driven by a shaft I I. The shaft i4 is acontinuation of the shaft of a motor it, which motor is disposed belowthe pump bowls and connected to and supported from the lower of thebowls by an interposed strainer I8 and a suction nozzle I9, the strainerhaving wall slots or other openings 20 through which the water which ispumped enters the suction end of the bowls I2.

The motor I6 is of sealed type adapted for submergence and includes acasing which for construction, assembly, and access to the parts,

may be divided into a lower section II, an intermediate section HA, anda seal section IIB. The sections i'I, IiA and HE may be coupled togetherand secured to the strainer I8 by studs 22 and nuts 22A. The casing isclosed at its lower end by a lower head 24, which supports the lower endof the shaft I4 through an annular bearing 26, an annular bearingretainer housing 21, and an annular bearing 28 which journal the shaft.The head 24 preferably includes a depending sump portion 24A whichcommunicates with the casing through openings 2413.

The casing of the section I? is provided at its upper end with aninwardly extending annular flange 30, and the intermediate section IIAhas an intermediate head portion 32 which seats on this flange. The headportion 32 has a downwardly extending cylindrical portion 32A whichcarries at its lower end an upper bearing 34 for the shaft I4. Above thebearing, openings 32B extend through the cylindrical portion 32A, andabove these openings the head is chambered out concentrically around theshaft to receive and cooperate with an impeller 36 to form a pump forcirculating oil. The impeller is secured to, and driven by, the shaftI4, the openings 32B communicating the section Il with the intake of theimpeller.

The section I'IB includes an integral head which may comprise aninwardly extending annular flange 31, a downwardly continuingcylindrical wall portion 31A, and a central head portion 31B,terminating the cylindrical portion, the downwardly extending portionestablishing with the casing wall an annular surge chamber 310. The headportion is chambered out concentrically around the shaft to receive anannular flange portion 38A of a seal 38. The flange portion 38A of theseal seats on a gasket 40 disposed in the chambered out central portion313 of the head and is clamped against the gasket by an annular flange42 secured by screws 42A. The shaft l4 continues through the seal 38 andupward through the strainer [8 to drive the pump impellers (not shown)in the bowls l2.

The oil pump impeller 36 discharges through a tube 44 to the upper coil50 of a bank of coils 52 disposed in the strainer section 18 of thewater pump. The oil delivered to the upper coil of the bank fiowsdownward through the coils and a connecting tube 54 into the seal 38which is shown in sectional elevation in Fig. 4. The seal includesresilient annular sealing rings 56 which are disposed between annularshoes 58 and held in shaft contact by a coil spring 66 disposed betweenand bearing against the shoes and maintain an annular oil space 62around the shaft, into which space the tube 54 discharges.

The shaft i l, at least from the seal level to its lower end, has a bore64 which provides an oil passageway, and at the level of the annularspace E2 of the seal has lateral openings 66 establishing communicationbetween the annular space and the shaft passageway. At its lower end thepassageway discharges through the axial opening 68 in the bearingretainer 2? into the sump 24A. The motor may be filled with oil througha filling opening Ill. The motor [6 includes an annular stator 12 whichis carried by the casing section I1, and a rotor 14 which is mounted onand driven by the shaft 14, the rotor being externally cylindrical andseparated from the stator by the usual gap 16, which is open both topand bottom and establishes a connecting passageway from the lowerportion of the section I! to the upper portion thereof.

The coil 52 and other passageways, the sump 24A and the motor casing, toa level 31D about half the depth of the surge chamber 310, are filledwith oil and the motor put in operation. During operation the oil pumpimpeller 36 draws oil from the motor chamber and sump 24A and dischargesthe oil through the tube 44 and the upper coil 50 from which it returnsthrough the bank of tubes 52A.and the tube 54, seal 38 and bore 64 ofthe shaft, to the sump.

All oil drawn from below the stator-rotor level and the sump, must passthrough the gap It between stator and rotor and effect cooling action onthe coils. Thereafter the oil is forced through the coil 52, where it issubject to direct cooling action of the water drawn from the wellthrough the strainer i8 into the pump. All the cooled oil returns to thesump and is drawn therefrom through the rotor-stator gap to promotecooling where most needed. Adequate bearing lubrication is alsoinherently provided by flooding of the bearings.

In Fig. 3 the structure, including the oil pump 36 and parts therebelow,are identical with those previously described and carry the sameidentifying numbers. 1

Above the pump level a single casing section C may be used, whichsection is of substantially greater depth than the corresponding twosections previously shown and has associated there'- I31A ofcorrespondingly greater depth, establishing a relatively deep surgechamber [310 which acts as a cooling chamber.

The oil pump 36 discharges directly into the casing section 110. Areturn tube I54 leads from the surge chamber into the seal 38, which issubstantially as shown in Fig. 4 and previously described, but isinverted as regards Fig. 4 to facilitate connection of the return pipe.In this form of the device, primary reliance for cooling of the oil isplaced on contact of the oil with the wall of the casing section.Preferably the oil pump 36 discharges through a short discharge tube I56which is arcuately curved to discharge substantially circumferentiallyaround the casing wall and may be spiralled slightly upward. The motorsection is coupled to the pump bowls through a strainer section whichmay be identical with the strainer section l8 of Fig. 2, or be a sectionH8 of modified shape as indicated in Fig. 3. In the claims the surgechamber 31C of Fig. 1, or [31C of Fig. 3 will be also referred to as anexpansion or cooling chamber.

It will be understood that many of the details of construction of themotor section, as evidenced by differences in detail of the sectionsshown in Fig. 1 and Fig. 3, may be varied without departing from thespirit of our invention, and that except where a detail is definitelyset out in any claim or claims such detail may not be read into suchclaim or claims.

We claim:

1. In a deep well pump which includes pumping means, an intake sectionbelow and supported from said pumping means and a sealed typesubmersible motor substantially filled with oil supported by said intakesection, said motor including a casing, a vertical shaft, a rotor, and astator, said casing having a lower closure head including a dependingsump, an upper head through which said shaft extends to drivingengagement with said pumping means, and an intermediate head dividingsaid casing into a motor section and an expansion section; said upperhead including a seal surrounding said shaft and substantiallyhermetically sealing said casing; oil circulatin means including ahousing formed in said intermediate head around said shaft; a pumpimpeller secured on said shaft, disposed in and cooperating with saidhousing to form a centrifugal pump, said impeller having an intakefacing and communicating through said intermedi ate head with said motorsection, and said housing having a discharge opening in said expansionsection; a tubular cooling coil disposed in said intake section, a tubecommunicating said discharge opening with said coil, and a return tubecommunicating said coil into said seal; said shaft from said seal to itslower end, having a central bore and having openings communicating theinterior of said seal with said bore; said lower head having a centralopening into said sump underlying said shaft bore and additionalopenings communicating said sump and motor section.

2. In a deep well pump which includes pumping means, an intake sectionbelow and supported from said pumping means and a sealed typesubmersible motor substantially filled with oil supported by said intakesection, said motor including a casing, a vertical shaft, a rotor, and astator, said casing having a lower closure head including a dependingsump, an upper head through which said shaft extends to drivingengagement with said pumping means, and an in- 'termediate head dividingsaid easing into a motor section andan expansion section; said upperhead including a seal surrounding said shaft and substantiallyhermetically sealing said casing; oil circulating means including ahousing around said shaft carried by said intermediate head; a pumpimpeller secured on said shaft, disposed in and cooperating with saidhousing to form a centrifugal pump, said impeller having an intakefacing and communicating through said head with said motor section, andsaid housing having a discharge opening in said expansion section; atubular cooling coil disposed in the path of water drawn into andthrough said intake section by said pumping means, a tube communicatingsaid discharge opening with said coil, and a return tube communicatingsaid coil into said seal; said shaft from said seal to its lower end,

having a central bore and having openings communicating the interior ofsaid seal with said bore; said lower head having a central opening intosaid sump underlying said shaft bore and additional openingscommunicating said sump and motor section.

3. In a deep well pump which includes pumping means, an intake sectionbelow and supported from said pumping means and a sealed typesubmersible motor substantially filled with oil supported by said intakesection, said motor including a casing, a vertical shaft, a rotor, and astator, said casing having a lower closure head ineluding a dependingsump, an upper head through which said shaft extends to drivingengagement with said pumping means, and an intermediate head dividingsaidcasing into a motor section and an expansion section; said upperhead including a seal surrounding said shaft and substantiallyhermetically sealing said casing; oil circulating means including ahousing around said shaft carried by said intermediate head; a pumpimpeller secured on said shaft, disposed in and cooperating with saidhousing to form a centrifugal pump, said impeller having an intakefacing and communicating through said head with said motor section, andsaid housing having a discharge opening in said expansion section; atubular cooling coil disposed in said intake section in the path ofwater drawn into and through said intake section by said pumping means,a tube communicating said discharge opening with said coil, and a returntube communicating said coil into said seal; said shaft from said sealto its lower end, having a central bore and having openingscommunicating the interior of said seal with said bore; said lower headhaving a central opening into said sump underlying said shaft bore andadditional openings communicating said sump and motor section.

4. In a deep well pump which includes pumping means, an intake sectionbelow and supported from said pumping means and a sealed typesubmersible motor substantially filled with oil supported by said intakesection, said motor including a casing, a vertical shaft, a rotor, and astator, said casing having a lower closure head, an upper head throughwhich said shaft extends to driving engagement with said pumping means,and an intermediate head dividing said casing into a motor section andan expansion section; said upper head including a seal surrounding saidshaft and substantially hermetically sealing said casing; said casingenclosing an oil pump carried by said intermediate head and driven bysaid shaft; said pump including an intake communieating with said motorsection, and a discharge opening in said expansion section; a tubularcooling coil carried by said intake section in the path of water drawninto said intake section of said pumping means, a tube communicatingsaid discharge opening with said coil, and a return tube communicatingsaid coil into said seal; said shaft from said seal to its lower end,having a central bore and having openings communicating the interior ofsaid seal with said bore; said lower head having openings communicatingsaid shaft bore and said motor section.

5. In a deep well pump which includes pumping means, an intake sectionbelow and supported from said pumping means and a sealed typesubmersible motor substantially filled with oil supported by said intakesection, said motor including a vertical shaft, a rotor and a stator,

and a casing having a lower closure head including a depending sump, anupper head through which said shaft extends to driving engagement withsaid pumping means, and an intermediate head dividing said casing into amotor section and an expansion section; said upper head including a sealincluding axially spaced sealing rings surrounding said shaft andsubstantially hermetically sealing said casing; oil circulating meanswhich includes a housing forming part of said intermediate head; a pumpimpeller secured on said shaft disposed in and cooperating with saidhousing to form a centrifugal pump, said impeller having an intakefacing and communicating with said motor section, and said housinghaving a discharge opening in said expansion section; a tubular coolingcoil disposed in said intake section, a tube communicating saiddischarge opening with one end of said coil, and a return tubecommunicating the opposite end of said coil into said seal; said shaftfrom said seal to its lower end having a central bore and having alateral opening communicating the interior of said seal with said bore;said lower head having openings communicating said sump and said motorsection, and an opening into said sump underlying said shaft bore.

6. A submersible motor which includes a sealed oil filled casing and avertical hollow shaft journalled in said casing; said casing having aclosure head at its lower end, an upper head carrying a seal throughwhich said shaft projects, and an intermediate head dividing said casinginto motor and cooling chambers, a cylindrical rotor mounted on saidshaft, and a casing carried annular stator around and separated fromsaid rotor by an annular gap interconnecting upper and lower portions ofsaid motor chamber; oil circulating means including a housing carried bysaid intermediate head, and having a discharge opening into said coolingchamber, an impeller mounted on said shaft and disposed in said housing,said impeller including an intake opening leading from the upper portionof said motor chamber, said seal including a shell having an openingtherethrough into said cooling chamber, and said shaft having lateralopenings from said seal into said hollow shaft.

'7. A submersible motor which includes a sealed oil filled casing and avertical hollow shaft journalled in said casing; said casing having aclo- Sure head at its lower end, an upper head carrying a seal throughwhich said shaft projects, and an intermediate head dividing said easinginto motor and cooling chambers, a cylindrical rotor mounted on saidshaft, and a casing carried annular stator around and separated fromsaid rotor by an annular gap interconnecting upper and lower portions ofsaid motor chamber; oil

circulating means including a housing carried by said intermediate head,and having a discharge opening, a tube leading arcuately away from saidopening and terminating in substantially tangential relation to theshell of said cooling chamber, an impeller mounted on said shaft anddisposed in said housing, said impeller including an intake openingleading from the upper portion of said motor chamber, said sealincluding a shell having an opening therethrough into said coolingchamber, and said shaft having lateral openings from said seal into saidhollow shaft.

8. A submersible motor which includes a sealed oil filled casing and avertical hollow shaft journalled in said casing; said casing having aclosure head at its lower end, an upper head carrying a seal throughwhich said shaft projects, and an intermediate head dividing said casinginto motor and cooling chambers, a cylindrical rotor mounted on saidshaft, and a casing carried annular stator around and separated fromsaid rotor by an annular gap interconnecting upper and lower portions ofsaid motor chamber; oil circulating means including a housing carried bysaid intermediate head, and having a discharge opening into said coolingchamber, an impeller mounted on said shaft and disposed in said housing,said impeller including an intake opening leading from the upper portionof said motor chamber, said seal including a shell having an openingtherethrough, a tube connected to said shell and leading from saidopening upward to desired oil level in said cooling chamber, and saidshaft having lateral openings from said seal into said hollow shaft.

9. A submersible motor which includes a sealed oil filled casing and avertical hollow shaft journalled in said casing; said casing having aclosure head at its lower end, an upper head carrying a seal throughwhich said shaft projects, and an intermediate head dividing said casinginto motor and cooling chambers, a cylindrical rotor mounted on saidshaft, and a casing carried annular stator around and separated fromsaid rotor by an annular gap interconnecting upper and lower portions ofsaid motor chamber; oil circulating means including a housing carried bysaid intermediate head, and having a discharge opening, a tube leadingarcuately away fromsaid opening and terminating in substantiallytangential relation to the shell of said cooling chamber, an impellermounted on said shaft and disposed in said housing, said impellerincluding an intake opening leading from the upper portion of said motorchamber, said seal including a. shell having an opening therethrough, atube connected to said shell and leading from said opening upward todesired oil level in said cooling chamber, and said shaft having lateralopenings from said seal into said hollow shaft.

10. A submersible motor which includes a sealed casing and a shaftjournalled in said casing, said casing having a closure head at one end,an opposite head carrying a seal through which said shaft projects, andan intermediate head dividing said casing into motor and coolingchambers, a cylindrical rotor mounted on said shaft, and a casingcarried annular stator around and separated from said rotor by anannular gap interconnecting opposite portions of said motor chamber;pumping means, within said casing, driven by said shaft, said meansincluding an intake from said motor chamber adjacent said intermediatehead and a discharge opening into said cooling chamher, said shaftextending from said seal carrying head to adjacency with said closurehead, having a co-extensive bore and lateral openings into said boreadjacent said seal carrying head, said openings and said boreestablishing return flow from said cooling chamber into said motorchamber adjacent said closure head.

KENNETH E, MOEHRL. CHARLES B. PORTER, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,968,566 Moran July 31, 19342,002,916 Mendenhall May 28, 1935 2,043,236 Conant June 9, 19362,280,087 Hollander Apr. 21, 1942 FOREIGN PATENTS Number Country Date544,930 Great Britain May 4, 1942

